This research will contribute to our understanding of the formation of dental plaque in man. The biosynthesis of polysaccharides and their assembly into an integral cell wall will be studied in Streptococcus sanguis 34 (Ss34), a baterium isolated from human dental plaque. Ss34 was chosen because it coaggregates specifically with Actinomyces viscosus T14, an important oral pathogen, by means of a lectin-type interaction involving carbohydrate groups that are attached to the cell surface of Ss34. The structure oc chemical linkage groups that attach cell wall polysaccharides to Ss34 peptidoglycan will be determined. Characterization of these linkage groups, and an understaning of the metabolic pathway by whichhhhthese structures arise, may lead to the rational development of agents which could block the assembly of cell wall polymers into an integral cell wall. Therefore, the incorporation of radioactive sugars into lipopolymeric intermediates that are associated with the cellulr membrane will be assayed, and the intermediates will be isolated and identified. The possible secretion of lipopolymeric intermediates under conditions of normal growth or of antibiotic stress will be examed. Because cell wall polysaccharides may play an important role in plaque formation and in adherence of bacteria to oral tissues, and because secretion of lipopolymers might influence the establishment of the diseased state, the basic physiological data obtained in this investigation are expected to contribute to the establishment of a rational basis for the management of dental caries periodontal disease.